Select the most appropriate idiom that can substitute the underlined segment in the given sentence.
Read the books of APJ Abdul Kalam, who was a scholar.

The idiom "a man of letters" refers to a scholar, intellectual, or someone who is highly educated and well-versed in literature and writing.
* "A dare devil" is a reckless or dangerously adventurous person.
* "A queer fish" is a strange or eccentric person.
* "A man of straw" refers to someone who is weak, unreliable, or lacks substance.